There has been proposed, as an oral cleaning device capable of cleaning the oral cavity with a cleaning liquid ejected from a nozzle, a water flow type oral cleaning device which is provided with a pump capable of ejecting a cleaning liquid by the linear reciprocating motion of a piston, pump driving means which drives the piston, and an ejection nozzle for the cleaning liquid, and capable of efficiently cleaning, for example, interdental spaces and periodontal pockets with the cleaning liquid by jetting the cleaning liquid from the nozzle (refer to Patent Documents 1 and 2, for example).
In oral cleaning devices described in Patent Documents 1 and 2, a cleaning liquid can be ejected from a nozzle by the reciprocating motion of a piston. For example, the cleaning liquid is filled into a cylinder when the piston moves forward and the cleaning liquid inside the cylinder is ejected from the nozzle when the piston moves backward. Accordingly, the cleaning liquid is intermittently ejected from the nozzle so that the cleaning liquid pulsates. Thus, these oral cleaning devices have the following advantage. When periodontal pockets are cleaned, a cleaning liquid supplied into the periodontal pockets is discharged from the periodontal pockets between ejection operations of the cleaning liquid, that is, when the ejection of the cleaning liquid is stopped. Thus, it is possible to reduce collision of the cleaning liquid inside the periodontal pockets to thereby allow a kinetic energy of the cleaning liquid when ejected from the nozzle to efficiently act on the periodontal pockets, compared to a case in which a cleaning liquid is continuously ejected from the nozzle without changing the flow rate. As a result, the periodontal pockets can be effectively cleaned.
Further, there has also been proposed an oral cleaning device which is configured in such a manner that an air pump for feeding air is disposed on a cleaning liquid supply passage on the downstream side with respect to a piston type pump to mix air into a cleaning liquid ejected from a nozzle so that a touch feeling caused by the cleaning liquid to gums can be softened and a comfortable feeling that cannot be obtained only by the cleaning liquid can be obtained (refer to Patent Document 3, for example).
On the other hand, there has also been proposed an oral cleaner which is configured to eject a cleaning liquid by a manual air pump (refer to Patent Document 4, for example). In this oral cleaner, an impeller which is rotated by water pressure of a cleaning liquid is disposed on the midway part of a cleaning liquid supply passage leading from a cleaning liquid tank to a nozzle to pulsate the cleaning liquid ejected from the nozzle to thereby improve the cleaning effect.